采用悬浮生长型和两种附着生长型膜生物反应器（MBR）处理微污染源水，考察了各种MBR的膜污染特征及清洗情况。通过电镜观察污染膜表面，发现不同MBR 的膜外表面污染特征不同，而膜内表面均无明显污染。对污染膜进行物理和化学清洗试验表明，常规物理清洗可使滤饼层大部分脱落，但对膜过滤性能的恢复效果较差；碱洗对膜过滤性能的恢复作用显著，有机污染对膜阻力的“贡献”最大。附着生长型MBR的污染膜表面粘性较大，常规物理清洗效果差，采用超声波清洗可使膜过滤性能恢复约30%，与超声波结合的化学清洗效果优于常规化学清洗。对膜污染化学洗脱液成分的分析表明，MBR中的膜污染与混凝—微滤膜组合工艺（C-MF）相比，有机污染物含量较高，Ca元素含量较低，腐殖质组分略高。两种工艺条件下洗脱液中溶解性有机污染物均以小分子有机物为主；与C-MF 相比，MBR的膜污染洗脱液中大分子有机物增多，推测与反应器内微生物代谢产物的产生有关。

The kinetics of quinoline degradation by O3/UV in aqueous phase was studied in this paper. It was found that the stoichiometric factor for the number of ozone molecule consumed by per quinoline molecule was 1. The second-order rate constants at 15℃ for the direct reaction of quinoline with ozone and that for the reaction of quinoline with. OH were determined to be 51.0 and 7.24×109M-1 s-1, respectively. In O3/UV reaction system, -OH was the more important oxidant to degrade quinoline than ozone. For a comparison, in O3 reaction system, the relative imp ortance of the two oxidants depended on the pH value greatly. To make the degradation of quinoline more practical, improvement of the concentration of. OH is more feasible.

In order to clarify the dependence of apparent adsorption constant Ks in the Langmuir-Hinshelwood (L-H) model on the incident light intensity, photocatalytic degradation kinetic characteristics were experimentally investigated at different light intensities using para-chlorobenzoate (4-CBA) as a model compound. In all cases 4-CBA initial degradation rates showed dependence on 4-CBA initial concentration, which can be described by the L-H model. However, the adsorption constant Ks and rate constant kr obviously varied with light intensity. To account for the experimental finding, slight modification of the classic kinetic model developed by Turchi and Ollis was tentatively proposed by assuming insufficiency of H2O/OH-available for photo-activated holes' scavenging. Such a kinetic model predicts that both kr and Ks-1 are linearly proportional to the square root of the intensity in a rather large intensity range. The validity of the modified model was proved by fitting it to the experimental data. #2002 Elsevier Science Ltd. All rights reserved.

The influence of hydrodynamic conditions on membrane fouling was investigated. Ten experiments were dsigned and operated over a wide range of suspended solid (SS) concentrations (2-20 gl-1), iltration fluxes (4.5-271m-2h-1) and aeration intensities (10-100m3 m-2 h-1). In each experiment, the liquid cross-flow velocity was measured and the membrane filtration resistance was monitored. A modified model was set up for calculating the cross-flow velocity of the activated sludge over the membrane surface. The increasing rate of filtration resistance was deduced as a power function of the cross-flow velocities, filtration fluxes and SS concentrations, and a critical curve corresponding to a group of critical fluxes and critical aeration intensities was found. The membrane filtration resistance sharply increased at a flux over the critical flux or at an aeration intensity below the critical aeration intensity.

The membrane fouling characteristics and cleaning strategies in a coagulation-microfiltration combination process for purification of micro-polluted raw water were investigated. The microcosmic observation on the exterior and inner surfaces of the fouled membrane by Scanning Electronic Microscope (SEM) combined with Energy Dispersive Spectrometer (EDS) revealed that the fouling on the exterior surface was an integrated effect of microorganisms, organic and inorganic matters, while that on the inner surface was mainly due to the bio-fouling. The investigation on the recovery of the membrane permeability with various cleaning methods showed that alkaline cleaning effectively removed most of the microorganisms and organic foulants formed on both the exterior and inner surfaces of the membrane, and acidic cleaning more effectively removed the inorganic scales. Based on the analysis of the extracted solution during chemical cleaning, it was found that the majority of soluble organic foulant were of low molecular weight, and Ca was the ma.jor inorganic element in the foulants.